Abstract:

Abstract:In order to explore novel nitrogen-rich heterocyclic energetic compounds， an amide bridged energetic compound 1-hydroxy-N-（1H-1，2，4-triazol-3-yl）-1H-tetrazole-5-carboxamide was synthesized from 5-cyano-1-（1H-1，2，4-triazol-5-yl）-1H-tetrazole through several steps involving amidoximation， diazotization， substitution and electrophilic addition. Its structure was fully characterized by nuclear magnetic resonance （NMR）， Fourier transform infrared spectroscopy （FT-IR） and elemental analysis （EA）. X-ray diffraction analysis （SC-XRD） was adopted to further confirm its structure； its thermal decomposition process was studied by differential scanning calorimetry （DSC） and thermogravimetry （TG）. The compound has a high onset decomposition temperature of 265 ℃ and shows good properties with detonation velocity of 8017 m·s^-1， and detonation pressure of 23.1 GPa， impact sensitivity of 20 J， and friction sensitivity of 288 N.

Abstract:In order to investigate the effect of aggregation structure on the properties of hexanitrohexaazaisowurtzitane/octogen （CL?20/HMX） co?crystal， the droplet confined crystallization was used to prepare spherical CL?20/HMX co?crystal. The morphology and structure of the samples were characterized by field emission scanning electron microscopy （FE?SEM）， X?ray powder diffraction （XRD） and fourier transform infrared spectroscopy （FT?IR）. The properties of the samples were analyzed by thermal analysis， sensitivity and combustion tests. The results show that the spherical CL?20/HMX co?crystal was successfully prepared by this method. The diameter of the spherical CL?20/HMX co?crystal is 1.3-1.85 mm， the hollow ratio is about 40%， and the specific surface area is 6.890 m2·g-1. The exothermic peak temperature of spherical CL?20/HMX co?crystal is located at 245.8 ℃ ， the thermal decomposition activation energy （463.02 kJ?mol-1） and the critical temperature of thermal explosion （241.28 ℃） are higher than those of flake CL?20/HMX co?crystal， exhibiting the excellent thermal stability of spherical CL?20/HMX. The impact sensitivity is better than that of raw material and flake CL?20/HMX co?crystal， and the friction sensitivity falls between raw CL?20 and HMX， but lower than that of flake CL?20/HMX co?crystal. The ignition delay time is less than 8 ms and the combustion is efficient and stable， while the flake CL?20/HMX co?crystal， raw materials and their physical mixture exhibit flameless combustion.The construction of millimeter?sized hollow spheres for CL?20/HMX co?crystal has significantly improved the thermal stability，sensibility and combustion performances.

Abstract:In order to improve the dispersibility and energy output of nano-boron powder， n-B/NC/F₂₆₀₂ core-shell nanofibers were prepared by coaxial electrospinning method. The morphology of the samples prepared with different core solution mass fraction， shell solution mass fraction， working voltage， distance from needle to collector and injection rate were analyzed by scanning electron microscope（SEM）， and the optimum preparation conditions were explored. Scanning electron microscope （SEM）， X-ray photoelectron spectrometer（XPS） and infrared spectrometer （IR） were used to analyze the morphology of the samples prepared under the best preparation conditions. The combustion performance test， thermodynamic simulation and DSC-TG were used to analyze the combustion performance. The results show that the optimum preparation conditions is 15% of the core layer solution， shell solution mass fraction 15%， working voltage 16 kV， distance between needle and collector 12 cm， core flow rate 3.6 mL·h^-1， shell flow rate 6 mL·h^-1. The average diameter of the spinning product was 1.32 μm. The combustion performance test shows that the highest peak of combustion pressure is 0.51 MPa， and the average pressure boost rate is 0.61 MPa·s^-1， showing excellent combustion performance. Thermodynamic simulation showed that the average molecular weight of the product was 29 g·mol^-1， and the combustion was sufficient. DSC-TG showed that the weight gain of boron in n-B/NC/F₂₆₀₂ was 43.43% more than that of the original boron powder， and the peak exothermic temperature of boron in n-B/NC/F₂₆₀₂ was 41 ℃ lower than that of the original boron powder. The coaxial electrospinning method could better optimize the nanostructure of the fibers.

Abstract:To investigate the influence of SiC mass fraction， SiC particle size， Al particle size， and their interactions on the mechanical properties of PTFE/Al/SiC （PAS） reactive materials， a 2³ factorial design criterion was employed to design and prepare eight different compositions of PTFE/Al/SiC reactive materials， and quasi-static compression tests and split Hopkinson pressure bar （SHPB） experiments were conducted. Significant factors were selected using the t-value ranking method， and their contribution rates and disturbance trends were analyzed. Additionally， response surface methodology was employed to analyze significant interaction effects. The results indicate that a higher SiC mass fraction positively impacts the mechanical properties of PAS materials. With a sudden change of strain rate， SiC particle size exhibits opposite disturbance trends on the material mechanical response. The effect of Al particles on the mechanical response of the PAS material system is limited. Strong interaction effects between factors should not be overlooked. With low strain rate loading， the interaction between SiC mass fraction and SiC particle size is significant. When the SiC mass fraction is high and the particle size is small， the particle dispersion state and interfacial bonding strength can be optimized， thereby improving material mechanical response. With high strain rate loading， PAS materials with a higher SiC mass fraction exhibit higher dynamic mechanical response， and the interaction between SiC particle size and Al particle size is significant. When the particle sizes of SiC and Al are close， the dynamic response of the material can be effectively improved.

Abstract:A new type of cannon barrel with spiral grooves structure has been designed based on the principle of gas-curtain launching to reduce the launch resistance of underwater cannons. The low-resistance and high-speed launch of underwater cannons was achieved by the four spiral grooves opened on the inner wall of the barrel. A transient three-dimensional two-phase flow model of the gas-curtain launching and drainage process of underwater cannons was established， and the rationality of the model was verified. Based on this， numerical simulations of the drainage process of the spiral grooves structure were conducted， and the effects of straight grooves and spiral grooves on the gas-curtain drainage were compared and analyzed. The results show that during the initial expansion stage， the four gas jets rotate circumferentially and rapidly expand radially along the spiral grooves structure. Then， the jets interfere with each other and gradually converge， forming a columnar gas-curtain and starting· the cooperative drainage. During the formation of the gas-curtain， the spiral groove structure has a complex effect on the expansion velocity of the jet head， presenting an initial sharp decrease and subsequent decline with fluctuations. After the formation of the columnar gas-curtain， the velocity of the gas-curtain head increases nonlinearly. When the gas-curtain head expands to the outlet， the gas content of the spiral groove barrel increases by 9.3% compared to the straight groove barrel. Especially， the gas content reaches 100% within the range of 400 mm in front of the projectile.

Abstract:A lateral annular slit charge was proposed in order to improve cutting effect in hard rock tuunels. Firstly， the blasting effects of the charge were analyzed theoretically. Then， the distributions of blasting strain and blasting crack after the charge blasting were studied through the model experiments. Finally， field tests were implemented to explore the applied efficacy of the charge. Results showed that the lateral annular slit charge could induce an energy accumulation effect at the slit position， which results in the rock mass at the slit position being subjected to stronger blasting loads and thus having stronger crack propagation ability. The lateral annular slit tube could reduce the blasting strain in the non-slit direction and increase the blasting strain in the slit direction. The strain distribution characteristic proves the energy accumulation phenomenon in the slit direction of the lateral annular slit charge. According to the macroscopic crack propagation， the crack propagation ability of lateral annular slit charge in the slit direction has been significantly improved. Compared with conventional column charge cutting blasting technique， the lateral annular slit charge cutting blasting technique could improve drivage efficiency and reduce cost in hard rock tunnels， which verifys that the lateral annular slit charge is preferred in hard rock tunnel cutting blasting.

Abstract:In order to determine the composition and content of eluent wastewater from the production of nitroglycerin/1，2，4-butanetriol trinitrate （NG/BTTN） mixed nitrate， a high performance liquid chromatographic （HPLC） gradient elution method was carried out to detect washing wastewater. The chromatographic conditions were determined as follows： the stationary phase was C18 （250 mm×4.6 mm， 5 μm） column， the mobile phase was acetonitrile/water solution， and and the detection wavelength was 200 nm. The results showed that six organic compounds were detected in the scrubber wastewater. By fitting the retention time of the compounds and their linear relationship with the partition coefficient LogD （27 samples were taken within 7 days）， it was determined that in addition to NG and BTTN， the following compounds were present in the scrubber wastewater from the production of mixed NG/BTTN nitrates： 1，2-dinitroglycerol（30.58%-41.20%）， 1，3-dinitroglycerol（110.69%-135.14%）， 1，2，4-butanetriol-1，2-dinitrate（7.90%-10.63%）， and 1，2，4-butanetriol-1，4-dinitrate（22.55%-27.95%）， with the standard deviations lower than 10%， and the method was sampled for 40 times within 10 d. It was proved that the method is accurate， reliable and applicable， and meets the testing needs of industrial production.

Abstract:Quantitative characterization of its physical structure is crucial for regulating and enhancing the performance of PBX. Utilizing micro-CT， image processing， and statistical analysis， we researched the quantitative acquisition of characteristic parameters for molding granules. We conducted research on image processing and statistical analysis to quantitatively obtain the characteristic parameters of molding granules based on micro-CT. The characteristic parameters of TATB-based molding granules were characterized by this method， and an evaluation of the characterization method was conducted. The results suggest that this method can implement the quantitative characterization of the size， morphology， porosity， density， and packing characteristics of the molding granules. The granule size and sphericity of the TATB-based molding granules approximately follow the exponential Gaussian and Weibull distributions， respectively. The intrinsic density is 1.35 g·cm^-3， with a visible porosity of 2.3%（@spatial resolution 14.3 μm）， and a volume fraction of 0.69. Evaluation experiments demonstrate that the method exhibits good accuracy， stability， and repeatability. The characterization results of granule size are consistent with those of the sieving process， and the relative deviation of the characterization results of main characteristic parameters in different periods is less than 1%. The results of morphology and properties are relatively significantly influenced by the packing state of granules and the spatial resolution of micro-CT.

Abstract:In order to understand the flow state of supercritical carbon dioxide （SC-CO₂）-assisted double-base propellant within the metering section during extrusion， and to analyze the distribution and variations of parameters such as pressure， fluid velocity， shear rate， and shear viscosity in the flow field， the CFD simulation software Polyflow was employed for simulating the flow state of the material in the metering section during SC-CO₂-assisted double-base propellant extrusion. The results show that both fluid pressure and shear viscosity decrease with increasing process temperature， gas injection rate， and solvent ratio. An increase in screw speed leads to a decrease in shear viscosity but a sharp increase in fluid pressure. The pressure on the outer wall of the fluid gradually increases in steps， with pressure at the cross-section exhibiting an approximately annular distribution， decreasing gradually from the inner wall of the barrel towards the screw surface. The shear viscosity at the cross-section forms a ring-shaped high-viscosity zone on the center of the screw. The closer the zone is to the inner wall of the barrel and the screw surface， the smaller the shear viscosity. Furthermore， changes in process parameters do not affect the distribution pattern of shear viscosity. The shear rate on the outer wall of the fluid increases with higher screw speed and concentrates at the thread. The maximum fluid velocity at the cross-section occurs near the thread， while the fluid velocity close to the inner wall of the barrel is minimal. As one moves away from the inner wall of the barrel and the screw surface， fluid velocity rapidly increases， with a greater gradient observed in zones closer to the screw surface and the inner wall of the barrel.

Abstract:Aiming at the lack of reliability quantitative design method of the Exploding Foil Initiator （EFI）， the reliability design method for the Four-point Array output interface of EFI is studied. Firstly， based on the Stress-strength interference model， the reliability quantitative design method considering double margin coefficients is proposed， and the quantitative model between output performance parameters and reliability index is constructed. Then， the output performance of the output interface on different design parameters is simulated， and the quantitative models between the output performance parameters and structural design parameters is established. Finally， combined with the above two types of quantitative models， the structural parameters that meet the requirements of the output interface reliability design index of the four-point array slapper detonator are given. The results show that the method can effectively improve the reliability design accuracy of EFI’s output interface and then achieve accurate design.